1. Field of the Invention
This invention relates to thin film magnetoresistive (MR) heads and more particularly to magnetoresistive (MR) head structures.
2. Description of Related Art
U.S. patent No. 5,639,509 of Schemmel for “Process for Forming a Flux Enhanced Magnetic Data Transducer” shows a two layered bottom pole structure formed by top shield and the flux enhancement layer. The flux enhancement layer is composed of with a magnetic High Moment Material (HMM) such as FeN and CoNiFe formed over a magnetic Permalloy-Like Material (PLM) top shield layer. A flux enhanced data transducer and method for producing the same in conjunction with Ashared shields on magnetoresistive (MR) read heads (in which substantially between 500 Å–2500 Å of a relatively higher magnetic moment material such as FeN and CoNiFe is added to the upper surface of the shared shield, or bottom write head pole, prior to a magnetic flux containment ion milling operation utilizing the upper pole as a mask) are described. The relatively higher magnetic moment flux enhancement layer may comprise CoNiFe, FeN or similar material which is deposited prior to the formation of the dielectric gap layer. The upper pole may be formed of NiFe deposited on a thin film seed layer of a 1 Å thick layer of a material such as NiFe or “may also comprise FeN or other relatively higher magnetic moment material such as CoNiFe.” The flux enhancement layer may then be selectively removed substantially surrounding the upper pole by means of a relatively brief ion milling process in which only on the order of 1,000 Å of the layer need be removed and during which only an insignificant amount of the material removed might be re-deposited on the sides of the upper pole.
U.S. Pat. No. 5,606,478 of Chen et al. for “Ni45Fe55 Metal-in-Gap Thin Film Magnetic Head” and U.S. Pat. No. 5,812,350 of Chen et al. for “Metal-in-Gap Thin Film Magnetic Head Employing Ni45Fe55” show a pole piece P1 composed of a combination of HMM and LMM materials.
U.S. Pat. No. 5,435,053 of Krounbi et al. for “Simplified Method of Making Merged MR Head” shows a method for making a planarized merged pole.